This invention relates to a part for use in fluid handling, which part moves relative to another part. The invention particularly relates to a valve seat, seal, bearing or the like. Such parts are commonly made of rubber or a similar elastomer, or of polytetrafluoroethylene (PTFE). The invention relates specifically to a a material composed of a polymeric material and a powdered metal comprising grains of titanium carbide (TiC) dispersed through a metal matrix. A part made of such a material can replace an existing rubber or PTFE part and yield a longer life.
Materials composed of a polymeric material mixed with a powdered metal are well known. U.S. Pat. No. 1,998,892 discloses a mixture of metallic shreds, mineral lubricants, lubricating oil, and flaked or powdered metal with rubber or rubber cement to form a packing ring. The rubber serves as a binder to retain the metal flakes.
In U.S. Pat. No. 2,691,814 polytetrafluoroethylene (PTFE) in sheet or powder form is forced into a porous metallic structure by heating and applying pressure to the PTFE to form a bearing material not needing oils for lubrication. The powdered PTFE may also be mixed with a powdered metal capable of being sintered below the disassociating temperature of PTFE. However, the mixture must be sintered in an atmosphere of cracked ammonia at 360.degree. C., using metal grains less than 149 micron size, and soft metals such as copper, tin, and lead are used.
Sintered PTFE particles may also be combined with carbon-fiber reinforced polyphenylene sulfide and heated to form injection molded floating ring seals for fluid sealing of rotating shafts as in U.S. Pat. No. 4,050,701. The surface of the seal must be machined to make available the lubricative properties of the dispersed PTFE. The PTFE particles used are of a relatively large size of 396-793 microns, and sintering is required for the PTFE to mix with the polyphenylene sulfide.
A seal member made of PTFE resin, containing iron alloy powder is shown in U.S. Pat. No. 4,098,515. The member is used as an abrasion-resistant oil seal ring, especially suitable for use on rotating shafts of aluminum or aluminum alloy. Also disclosed therein is the use of chromium molybdenum steel powder instead of cast iron powder.
The powdered metal of the type used in the present invention is disclosed in Prill U.S. Pat. Nos. 3,713,788 and 3,715,792. U.S. Pat. No. 3,713,788 discloses an age-hardenable, corrosion and heat resistant nickel-chromium matrix with TiC dispersed therein. U.S. Pat. No. 3,715,792 discloses a corrosion and wear resistant high-chromium matrix with TiC dispersed therein. Alloys such as these are commercially available from Chromalloy American Corporation under the trademark Ferro-Tic.